*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
li{
    list-style: none;
}
a{
    text-decoration: none;
}
.box{
    width: 600px;
    height: 400px;
    position: relative;
    margin: 100px auto;
    overflow: hidden;
}
.box .lunbo{
    display: flex;
    position: absolute;
}
.box .lunbo img{
    width: 600px;
    height: 400px;
}
.l,.r{
    width: 40px;
    height: 40px;
    background-color: rgba(0, 0, 0, 0.4);
    font-size: 30px;
    color: red;
    text-align: center;
    line-height: 40px;
    /* 子绝 */
    position: absolute;
    top: 180px;
    
}
.l{
    left: 10px;
}
.r{
    right: 10px;
}
.box ol{
    position: absolute;
    margin-left: 275px;
    bottom: 20px;
    display: flex;
}
.box ol li{
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background-color: #fff;
    margin-left: 10px;
}